Most stories of celebrity dogs seem to fall into one of two categories. The first seems to be the Hachiko-type, where a dog is noted for its loyalty to a master, especially when it extends past said owner's death. The other seems to be the one where a pooch's personality is so charming that an entire community collectively adopts it and does its best to give them the best life possible. The respective celebrity dogs of twin cities Edinburgh, Scotland and San Diego, California, represent both types perfectly.

Edinburgh has Greyfriar's Bobby, who was famous for sleeping on his owner's grave following his death. San Diego has Bum, a stray dog famous for having arrived in the city as a stowaway and beloved to many of the locals who fed and looked after him. While Bobby would be idealized by Victorian culture for his loyalty, Bum's rags-to-riches tale would resonate with late 19th-century United States attitudes.

Bum's story begins with him likely being born in San Francisco and arriving in San Diego after boarding a boat. Seen as a mutt, Bum was mostly left to his own devices and was a scrappy stray. When he got into a fight with another dog that led to both of them being hit by a train, a local veterinarian amputated one of Bum's front legs, and it's said his personality changed after the incident.

It seems Bum's accident gave him a bon-vivant attitude, as he began to ignore food handed out to him that did not interest him but would gladly accept more elaborate treats. He would also show up to high society parties and gained such fame that his image adorned all pet licenses issued in San Diego. Bum eventually died in 1898 and was honored with a sculpture in the iconic Gaslamp District.

In 2008, to commemorate their relation as sister cities, Edinburgh was gifted with a sculpture of Bum, while San Diego received one of Bobby. San Diego's Bobby now stands close to the original Bum in the Gaslamp District. Meanwhile, Edinburgh's Bum is a bit more distant to Bobby (whose memorial is located just outside Greyfriars Kirkyard off the Royal Mile), having been placed along one of the entrances to the iconic Princes Street Gardens.

Update as of May 2021: The statue has been moved to the grounds of St Cuthbert's Church off Lothian Road, it can be seen close to the church's Princess Street Garden gate. The plaque has not so far been resisted.